Download Configuration of the Four Parasympathetic Ganglia of the Head

MOJ Anatomy & Physiology
Configuration of the Four Parasympathetic Ganglia of the
Head
Opinion
Abstract
The ciliary, pterygopalatine, submandibular, and otic ganglia lie in the head
and they are parasympathetic in function. Each has sensory, sympathetic and
parasympathetic roots. However, the otic ganglion has an additional motor root.
Branches of the ciliary ganglion are named the short ciliary nerves while those
of the pterygopalatine ganglion are termed the orbital, pharyngeal, palatine and
nasopalatine nerves. On the other hand, branches of the submandibular and
otic ganglia are unnamed. The pterygopalatine ganglion is sometimes clinically
referred to as the “ganglion of hay fever”.
Keywords: Parasympathetic Ganglia; Ciliary; Pterygopalatine; Submandibular;
Otic
Introduction
The four parasympathetic ganglia of the head are related to
three out of the four cranial nerves that have parasympathetic
activities: the oculomotor (III), the facial (VII) and the
glossopharyngeal (IX) nerves. These ganglia include the ciliary, the
pterygopalatine, the submandibular, and the otic ganglia. There is
a general plan for the configuration of these ganglia. Each ganglion
is suspended from a branch of the trigeminal (V) nerve. Each has
three roots: sensory, sympathetic and parasympathetic; the otic
ganglion, in addition, has a fourth motor root. The cell bodies of
the sensory root lie in the trigeminal (Gasserian) ganglion, those
of the sympathetic root lie in the superior cervical sympathetic
ganglion, and the cell bodies of the parasympathetic root lie
in one of three parasympathetic nuclei in the brainstem. The
parasympathetic root relays within the ganglion; so it is formed
of preganglionic fibers whereas the sympathetic root does not
relay, as its fibers are postganglionic. Furthermore, the sensory
root runs through the ganglion, without a relay, in a direction
opposite to that of each of the parasympathetic and sympathetic
roots. The sympathetic root is derived from a plexus around
either of the external or internal carotid arteries. After receiving
roots, each parasympathetic ganglion gives branches that contain
the three types of the received fibers: sensory, sympathetic and
parasympathetic.
The Ciliary ganglion
The ciliary ganglion lies close to the medial wall of the orbit. It is
suspended, by a sensory root, from the nasocciliary nerve that is a
branch of the ophthalmic nerve (the 1st division of the trigeminal
ganglion). The ciliary ganglion receives its sympathetic root from
the plexus around the ophthalmic artery, which in turn is derived
from the internal carotid artery plexus. The parasympathetic root
for the ciliary ganglion arises, in the midbrain, from the EdingerWestphal nucleus of the oculomotor (III) nerve, passes through
this nerve to its inferior division then to the nerve to the inferior
oblique muscle of the eye that gives the parasympathetic root.
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Volume 2 Issue 5 - 2016
Department of Anatomy and Embryology, Cairo University,
Egypt
*Corresponding author: Heshmat SW Haroun, Department
of Anatomy and Embryology, Cairo University, Egypt, Email:
Received: May 07, 2016 | Published: June 07, 2016
The branches of the ciliary ganglion, named the “short
ciliary nerves”, pierce the eyeball around the optic nerve. Their
parasympathetic component fibers supply two intraocular
muscles: the constrictor (sphincter) pupillae and ciliary muscles.
The sensory fibers in the short ciliary nerves carry sensations
from the conjunctiva and cornea (corneal reflex) while the
sympathetic fibers supply the ocular blood vessels. It is worthy to
note that sympathetic fibers going to the dilator pupillae muscle
are found to come directly through the long ciliary branches of the
nasocciliary nerve.
The Pterygopalatine ganglion
The pterygopalatine ganglion lies in the pterygopalatine fossa.
Two sensory roots suspend it from the maxillary nerve that is the
second division of the trigeminal ganglion. The sympathetic root
is the “deep petrosal nerve” that arises from the internal carotid
artery plexus inside the carotid canal, emerges at the apex of
the petrous temporal bone, and crosses on the foramen lacerum
where it meets the parasympathetic root. The parasympathetic
root arises, in the pons, from the superior salivary nucleus of the
facial (VII) nerve. It is enclosed within the nervous intermedius
part of the facial nerve, to reach the geniculate ganglion of this
nerve that gives rise to the “greater superficial petrosal nerve”.
The latter emerges from the petrous temporal bone through the
hiatus and groove for greater superficial petrosal nerve to meet
the deep petrosal nerve on foramen lacerum. The two roots
(greater and deep petrosal) unite to form the Vidian nerve “nerve
to pterygoid canal” that passes through the pterygoid canal to
enter the pterygopalatine fossa and to join the ganglion from
behind.
The branches of the pterygopalatine ganglion include the
orbital branches that pass forwards through the inferior orbital
fissure, the pharyngeal branch that passes backwards through
the pharyngeal (palatinovaginal) canal, the greater and lesser
palatine nerves that descend through their canals, and the short
and long nasopalatine nerves that pass medially through the
MOJ Anat & Physiol 2016, 2(5): 00059
Configuration of the Four Parasympathetic Ganglia of the Head
sphenopalatine foramen. Eventually, these branches supply the
orbital periosteum, the lacrimal gland, the roof of nasopharynx,
the hard and soft palates, and the nose. In hay fever, irritation of
this ganglion leads to running nose and eyes.
The Submandibular ganglion
The submandibular ganglion lies, in the submandibular region,
on the hyoglossus muscle with the deep part and duct of the
submandibular salivary gland as well as the hypoglossal nerve
situated below it; all deep to mylohyoid muscle. Sensory roots
from the lingual nerve suspend the ganglion. The lingual nerve
is a branch of the posterior division of the mandibular nerve that
is the third and largest division of the trigeminal ganglion. The
sympathetic root for this ganglion comes from the facial artery
plexus that is derived from the external carotid artery plexus. The
parasympathetic root for the ganglion arises from the superior
salivary nucleus of facial (VII) nerve in the pons, runs through
the “chorda tympani” branch of facial nerve that escapes from
the tympanic cavity through the petrotympanic fissure into
the infra temporal fossa, to join the lingual nerve deep to the
lateral pterygoid muscle. Unnamed branches originating from
the submandibular ganglion either go directly to supply the
submandibular salivary gland or rejoin the lingual nerve to supply
the sublingual salivary gland and to carry taste sensation from the
anterior two-thirds of the mucous membrane of the tongue.
The Otic ganglion
Copyright:
©2016 Haroun
2/2
and both structures lie deep to the lateral pterygoid muscle in
the infratemporal fossa. The sympathetic root for this ganglion
comes from the plexus around the middle meningeal artery that
is a branch of the first part of the maxillary artery. This plexus
originates from the external carotid artery plexus. The inferior
salivary nucleus in the medulla oblongata gives rise to the
parasympathetic fibers of the glossopharyngeal (IX) nerve that
gives its tympanic branch (Jacobson’s nerve) that shares in the
formation of the tympanic plexus, which gives rise to the lesser
superficial petrosal nerve. The latter nerve emerges from the
hiatus and groove for the lesser superficial petrosal nerve (in the
petrous temporal bone), descends through foramen ovule of the
skull to join the otic ganglion as its parasympathetic root. The otic
ganglion has an additional motor root that arises from the nerve
to the medial pterygoid muscle, passes through the ganglion
without relay, and then emerges to supply tensor palati and
tensor tympani muscles. Unnamed branches of the otic ganglion
join the two roots of the auriculotemporal nerve to supply the
parotid gland.
The remaining cranial nerve that has parasympathetic function
is the vagus (X) nerve. It is related to none of the above-mentioned
four parasympathetic ganglia of the head. Its ganglia are terminal
close to or within the walls of the respiratory organs, the heart,
and the proximal part of the digestive tract.
The otic ganglion hangs from the medial (deep) aspect of the
main trunk of the mandibular division of the trigeminal nerve,
Citation: Haroun HSW (2016) Configuration of the Four Parasympathetic Ganglia of the Head. MOJ Anat & Physiol 2(5): 00059. DOI: 10.15406/
mojap.2016.02.00059